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DEPARTMENT OF COMMERCE 



Technologic Papers 

^ OF THE 

Bureau of Standards 

S. W. STRATTON. Director 



No. 185 

EXPERIMENTS ON COPPER CRUSHER 
CYLINDERS 



BY 



ALEXANDER I. KRYNITSKY, Associate Physicist 

Bureau of Standards 



FEBRUARY 1, 1921 




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1921 




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DEPARTMENT OF COMMERCE 



Technologic Papers 

OF THE 

Bureau of Standards 

S. W. STRATTON, Director 



No. 185 

EXPERIMENTS ON COPPER CRUSHER 
CYLINDERS 



BY 



ALEXANDER I. KRYNITSKY, Associate Physicist 

Bureau of Standards 



FEBRUARY 1, 1921 




PRICE, 10 CENTS 

Sold only by the Superintendent of Documents, Government Printing Office 
Washington, D. C. 



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GOVERNMENT PRINTING OFFICE 

1921 



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DOCtMEiNfS UIViolON 



41 



^li/fO 






EXPERIMENTS ON COPPER CRUSHER CYLINDERS 



By Alexander I. Krynitsky 



ABSTRACT 

The experiments consisted of compression tests on a standard Riehle testing machine. 
The results of these compressions carried out on annealed copper cylinders, one set 
having a mean length of 0.4000 inch and the others 0.5000 inch, with a mean diameter 
of 0.2260 inch in the former and 0.2500 and 0.2250 inch in the latter ones, suggest that 
the length of the cylinders decreased considerably under repeated application of the 
same and, within certain limits, of smaller loads. 

In the case where the load is applied in such a manner as to produce the maximum 
stress for only an instant, the duration of an appHcation of load has but little effect 
on the decrease in length of the cylinders, but the application of the same load by 
holding the beam balanced through an additional application of this load causes about 
twice the decrease in length as compared with that obtained by a single application of 
load. When two successive loads of considerable amount differing by increments of 
about 2000 pounds per square inch are applied, the second being greater than the first, 
the change in length due to the last load is greater than that obtained where the pres- 
sure is applied on previously uncompressed cylinders, and this difference decreases 
as the difference between the two loads successively applied increases, so that when 
the difference between the loads reaches a certain value the change of length due to 
the last load applied is practically independent of the previous load. 

It appears probable that aging at temperatures within the range 0-100° C softens 
the compressed copper somewhat. 

CONTENTS 

Page 

I. Introduction 4 

1. Two methods for measurement of pressure of gases in testing of 

powder and ammunition 4 

2. Copper crusher cylinders 6 

3 . Preparing data for tarage table 6 

4. Comparison of presstires indicated by dynamic and crusher-gage 

methods 7 

5. Necessity of preliminary precompression 7 

II. Compression tests 9 

1. Methods of compression 9 

2 . Measurement 9 

3 . Plan of designation 9 

4. Results of compression tests 10 

(a) Experiments on repeated application of same and of smaller 

loads 10 

(6) Experiments on effect of duration of compression applied 

tmder condition (i) 16 

(c) Experiments on effect of temperature of annealing 17 

(d) Experiments on influence of initial precompression when 

loads successively applied differ considerably from each 

other 19 

3 



4 Technologic Papers of the Bureau of Standards 

II. Compression tests — Continued Page 

4. Results of compression tests — Continued 

{e) Experiments on effect of initial precompression when 
differences between loads successively applied are only 
slight 20 

(/) Experiments on effect of duration of compression applied 
tmder condition (2) and comparison of the results of 
different methods of loading 23 

{g) Experiments on aging of copper cylinders of Series No. 2, 

Tables 19-25 25 

III. Microscopic examination 30 

IV. Summary 30 

I. INTRODUCTION 

1. TWO METHODS FOR MEASUREMENT OF PRESSURE OF GASES IN 
TESTING OF POWDER AND AMMUNITION 

Among many methods and apparatus ^ proposed for the meas- 
urement of pressure developed by the products of decomposition 
of powder in the testing of powder and ammunition there are two 
methods which up to the present time are commonly employed 
in practice; that is (i) the so-called dynamic method and (2) the 
method of measuring pressure by means of metallic cylinders, 
usually copper or lead cylinders, known as crusher cylinders. 

The dynamic method consists of determining the velocities of 
the gun in recoil or of the shot at different points of the bore. 
The difference of the velocities divided by the corresponding 
differences of the time equal the acceleration. The pressure 
required to produce the observed acceleration in a body whose 
mass is that of the gun or of the projectile is obtained by multi- 
plying the acceleration by the mass. 

The crusher-gage method was proposed in 1868 by Noble, and up 
to the present time is regarded as the most convenient known 
method for obtaining an idea of the relative values of pressiu-es 
in guns. 

There is a metal cylinder set on an anvil. On firing, the pressure 
of the gases shortens the cylinder longitudinally. The amount of 
this compression, with a previously prepared table, so-called tarage 
table, serves to determine the maximum pressure of the products 
of decomposition. For the testing of small arms a special barrel 
is used. For example, in Figs, i and 2, a pressure-gage outfit 

1 It may be mentioned here that two types of registering apparatus proposed very recently appear very 
promising, and they possibly will find common use in the near future. One of these was proposed by 
Prof. A. G. Webster, of Clark University, and the other is designed to coordinate time and pressure 
within a large cannon, upon which Dr. H. I,. Curtis and associates, of the electrical division of the Bureau 
of Standards, are working. 



Experiments on Copper Crusher Cylinders 







6 Technologic Papers of the Bureau of Standards 

for Russian 0.3 -inch revolver is shown : O = a special barrel; h = an 
unmovable piston fixed rigidly in its position by means of nut r 
and spring s; m=Si movable piston. Between pistons h and m 
crusher cylinders are placed. By turning the nut r the crusher 
cylinder may be tightened between these two pistons. 

2. COPPER CRUSHER CYLINDERS 

In the present paper only copper crusher cylinders will be con- 
sidered. Dimensions of copper cyHnders vary in different coun- 
tries and for pressure testing of different grades of ammunition 
and powder. 

For example, some dimensions of copper crushers are as follows: 



Dimensions 


A 


B 


C 


D 


Diameter 


mm 
3 

4.9 


mm 

8 
13 


Inch 

0. 2260 
.4000 


Inch 
0. 2520 


Height 


.5000 







The copper must be exceptionally pure, and the whole process 
of manufacture of copper crushers should be standardized with 
extreme care. 

3. PREPARING DATA FOR TARAGE TABLE 

In preparing these data the copper cyHnders are slowly com- 
pressed by applying the loads and measuring the amount of com- 
pression at each load. The load for each compression remains 
active for about 15 seconds. Ch. B. Wheeler,^ from his experi- 
ments, found it might safely be assumed that at the end of 15 
seconds the copper is practically in equilibrium with its load and 
that any further application of load produces no effect. 

Influence of the friction of the testing machine is of great 
importance in the construction of tarage tables. As early as 
1 89 1 this was demonstrated by Vieille, who showed that neglect 
of this factor was responsible for the erroneous French crusher 
tables. 

This point, states F. W. Jones, ^ must be insisted upon because 
experiments in some quarters assume friction is of no account, a 
conclusion to which they are driven because no provision has been 
made in the design of their testing machine for applying the load 
with friction acting alternately back and forth. 

^Report of Experiments with an 8-inch B. L. Rifle Momited on a Free Recoil Carriage, by Lieut. Ch. B. 
Wheeler, Ordnance Construction, Notes 69-85, pp. 46-56; Jan., 1896. 
3 A Standard Pressure Table for Copper Crushers, by F. W. Jones, Arms and Explosives, June i, 1918. 



Experiments on Copper Crusher Cylinders 7 

4. COMPARISON OF PRESSURES INDICATED BY DYNAMIC AND CRUSHER- 
GAGE METHODS 

The dynamic method shows a pressure which is less than the 
true pressure expected in the gun, as it takes no account of the 
pressure required to overcome the friction of the projectile in the 
bore and to rotate the projectile. 

Comparing now the dynamic method and the crusher-gage 
method, we find that the latter gives pressures which are less than 
those shown by the dynamic method. 

According to B. W. Dunn,* under ordinary service conditions 
(since the time required by powder pressiure to reach a maximum 
is less than 0.003 second or about o.ooi second) the probable 
errors with the crusher-gage method will be greater than 5000 
pounds per square inch. 

The quicker the powder the greater is the excess of actual over 
indicated pressures and, for this reason, the error of the crusher 
gage is greater for small arms than for cannon. 

5. NECESSITY OF PRELIMINARY PRECOMPRESSION 

Though the crusher-gage method is very old, there remains up 
to the present time a problem of great importance — the necessity 
of precompression. It has been stated by many experimenters 
that copper cylinders should be precompressed at a certain pres- 
sure before using for test. Capt. Blunt,^ F. W. Jones,^ Marshall,^ 
and others state that copper should be compressed beforehand 
with a static pressure only slightly less than that which it is to 
undergo in the actual test. 

Col. W. H. Tschappat^ states that when the pressure in the 
gun is high and quickly developed, it is at first very much greater 
than the resistance offered by the copper cylinder. The excess 
of pressure over resistance in this case accelerates the mass of the 
piston and develops considerable velocity in it. The energy of the 
piston due to this velocity is finally absorbed by further compres- 
sion of the copper; but in the early stages of compresssion the 
mass of the piston prevents as great a compression as would be 

* Report of Development of a Photoretardograph and Its Application to the Dynamic Measurement of 
Resistance to Compression Offered by the Copper Cylinders Used in Crusher Gages, by Lieut. B. W. 
Dunn, Ordnance Construction Notes, pp. 69-85; Jan. 13, 1896. 

f" Report of Capt. Blunt, Report of Chief of Ordnance, pp. 929-943; 1892. 

® F. W. Jones, Lectures to Young Gunmakers, Arms and Explosives, p. 58, April, 1901, and p. 139, March, 
1912. 

^ Marshall, Explosives, p. 363. 

8 Lieut, Col. W. H. Tschappat, Ordnance and Gunnery, pp. 101-103; i9i7- 



8 Technologic Papers of the Bureau of Standards 

obtained if the pressure acted directly upon the copper cylinder 
instead of through the piston. 

It is therefore desirable to reduce the energy of the piston as 
much as possible, and this may be done in two ways: By reducing 
its weight and by limiting its travel and accompanying velocity. 
As far back as 1883 Sarrau and Vieille ^ ^^ showed that defor- 
mation of copper cylinders depends upon the weight (mass) of 
the piston through which the presstue is communicated. Usually 
the piston is made as light as possible. 

To limit the travel all copper cyHnders are precompressed by a 
load, generally about 3000 pounds per square inch less than that ex- 
pected in the gun. According to many statements, initially com- 
pressed cylinders always record more uniform results than the 
uncompressed cylinders do. 

Many investigators are of the opinion that the influence of 
many factors which have an important bearing on the results of 
pressure testing are minimized by the use of initially compressed 
cylinders, and they beHeve also that it is to their advantage to 
check each cylinder by an initial compression. On the other hand, 
there is rather good evidence that very uniform results may be 
obtained with uncompressed cylinders when they are made 
extremely uniform. 

Thus, as was said above, the necessity of precompression up to 
the present time is rather an open question. In order to obtain 
some more data for the solution of this problem, experiments were 
started by the Biu-eau of Standards in connection with the stand- 
ardization of the crusher-gage method for pressure testing of 
small arms, ammunition, and powder." So far, the experiments 
have been confined to static tests; these are described in this 
paper. The experiments were carried out in 19 19; they consisted 
of a series of compressions of the cyHnders on a standard 10 000- 
pound Riehle Brothers testing machine, and some microscopic 
examinations of their longitudinal and cross sections. The results 
are given in the tables and diagrams, so that few explanatory 
notes are required. 

5 Sarrau et Vieille, Etude sur 1' Emploi des Manometres pour la Mesure des Pressions Developpees par le 
Substances Explosives. 

10 The Interior Ballistic, by Col. Pashkevitch, translated from Russian by Eieut. Tasker H. Bliss. 

" The standardization of the crusher-gage method was started by Dr. P. D. Merica imder the supervision 
of Dr. G. K. Burgess. 



Experiments on Copper Crusher Cylinders 9 

II. COMPRESSION TESTS 
1. METHODS OF COMPRESSION 

The rate of compression was always about 0.07 inch per minute. 
Duration of load after balance was obtained in most cases was 
about 2 }4 seconds, during which time the beam was not falling down. 

Two methods of applying the load were used: 

(i) There was single application of load. As soon as balance 
was obtained, the load was removed; or in some cases the load 
was removed after a certain period — 5 or 25 seconds. 

(2) After the balance was obtained, which was always followed 
by drop of the beam about 3 seconds after original balance, the 
balance of beam was maintained by reapplying the same load. 

2. MEASUREMENT 

The measurements were then made with a i/io 000-inch microm- 
eter. Measurements of length were taken with the cylinders 
placed in the micrometer centrally, each length being measured 
several times and only the minimum length recorded. Diameters 
were measured several times and the average recorded. After 
compression the cyHnders have a barrel shape and in some cases 
two diameters of each cylinder were measured; that is, diameter 
of base; also diameter of cross section midway between the bases. 

The diameter of the cross section midway between the bases 
is called ''maximum" in the tables, and, as was stated, it is an 
average value of several measurements. The diameter of the 
base is called "minimum" and is also an average of several meas- 
urements. The minimum diameter, because of the difficulty of 
obtaining the exact measurement, is only an approximate value. 

3. PLAN OF DESIGNATION 

There are two lots of copper crusher cylinders both annealed 
at 1200° F at the same plant, but at different times. These 
two lots are here called Series No. i and Series No. 2. 

There are also two other seis annealed at another factory at 1000° 
F and 1200° F, respectively, and called Series No. 3. The dimen- 
sions are given in inches, time in seconds, weight in pounds. Certain 
figures omitted were disregarded in drawing up the average as doubt- 
ful for various reasons. The following symbols will be used : 

L = initial length of cyHnders. 

D = initial diameter of cylinders. 

A = initial cross-sectional area. 

Li = length of cylinders after the first compression. 

L2 = length of cylinders after the second compression, and so on. 
21607°— 21 2 



lO 



Technologic Papers of the Bureau of Standards 



Di = diameter of cylinders after the first compression. 

2^2 = diameter of cylinders after the second compression, and 

so on. 
L— Li = change in length of cylinders after first compression. 
L—L2 = change in length of cylinders after the second com- 
pression, and so on. 

4. RESULTS OF COMPRESSION TESTS 

(o) EXPERIMENTS ON REPEATED APPLICATION OF SAME AND OF SMALLER LOADS 

TABLE 1. — ^Experiments on Repeated Application of Same and of Smaller Loads 

Li= length of cylinders after applying pressure of 30 000 lbs./in.2 for about 30 seconds. 
1.2= length of cylinders after applying pressure of 40 000 lbs./in.2 for about 30 seconds. 
L3= length of cylinders after applying pressure of (Note a) and (Note b) lbs./in.2 for about 30 
L4= length of cylinders after applying pressure of 38 000 lbs./in.2 for about 2}4 seconds. 
L5= length of cylinders after applying pressure of 36 000 lbs./in.2 for about 2}4 seconds. 
L6= length of cylinders after applying pressure of 34 000 lbs./in.2 for about 2}4 seconds. 
1.7= length of cylinders after applying pressure of 30 000 lbs./m.2 for about 2?,-^ seconds. 
L8=length of cylinders after applying pressure of 25 000 lbs./in.2 for about 2^ seconds. 



No. 


L 


D 


A 


Load 
equiva- 
lent to 
30 000 
lbs./in.2 


L-Li 


Di 
maxi- 


Load 
equiva- 
lent to 

40 000 
lbs./in.2 


L-L2 


Z>2 

maxi- 


Load 
equiva- 
lent to— 

(See a 
or b) 


L-Ls 


Load 

equiva- 
lent to 
38 000 
lbs./in.2 


1 


Inch 

0. 5004 
.5009 
.5003 
.5006 
.5004 
.4996 
.5009 
.5010 
.5013 
.5003 


Inch 

0. 2514 
.2516 
.2516 
.2517 
.2514 
.2516 
.2517 
.2517 
.2518 
.2517 


Inch2 

0. 0495 
.0497 
.0497 
.0497 
.0495 
.0497 
.0497 
.0497 
.0497 
.0497 


Lbs. 

1485 
1491 
1491 
1491 
1485 
1491 
1491 
1491 
1491 
1491 


Inch 

0. 0494 
.0490 
.0484 
.0485 
.0487 
.0482 
.0482 
.0501 
.0480 
.0492 


Inch 

0. 2672 
.2675 
.2675 
.2678 
.2669 
.2673 
.2677 
.2673 
.2672 
.2673 


Lbs. 

1980 
1988 
1988 
1988 
1980 
1988 
1988 
1988 
1988 
1988 


Inch 

0. 0814 
.0786 
.0786 
.0802 
.0786 
.0799 
.0799 
.0794 
.0786 
.0798 


Inch 

0. 2780 
.2778 
.2768 
.2781 
.2772 
.2784 
.2780 
.2777 
.2774 
.2777 


Lbs. 

a 1980 
a 1988 
a 1988 
1988 
a 1980 
&1888 
&1888 
5 1888 
&1888 
5 1888 


Inch 

0. 0816 
.0810 
.0823 
.0808 
.0820 


Lbs. 

1881 


2 


1888 


3 


1888 


4 


1888 


5 


1881 


6 


1888 


7 


1888 


8 


1888 


9 


1888 


10 


1888 






Average.. 










.0488 






.0795 






.0815 

























No. 


L-Li 


Di 
maxi- 
mum 


Di 
mini- 
mum 


Load 
equiva- 
lent to 

36 000 
lbs./in.2 


L-L, 


Load 
equiva- 
lent to 

34 000 
lbs./in.2 


L-L6 


Load 
equiva- 
lent to 
30 000 
lbs./in.2 


Di 
maxi- 
mum 


Dr 
mini- 
mum 


L-Lj 


Load 
equiva- 
lent to 
25 000 
lbs./in.2 


L-Ls 


1 


Inch 


Inch 

0. 2790 
.2790 
.2780 
.2800 
.2790 
.2790 
.2795 
.2790 
.2780 
.2785 


Inch 

0. 2669 
.2669 
.2660 
.2645 
.2660 
.2651) 
.2650 
.2669 
.2650 
.2660 


Lbs. 

1782 
1789 
1789 
1789 
1782 
1789 
1789 
1789 
1789 
1789 


Inch 

0. 0842 
.0851 
.0850 
.0862 
.0848 


Lbs. 
1683 
1690 
1690 
1690 
1683 
1690 
1690 
1690 
1690 
1690 


Inch 

0. 0861 
.0861 
.0859 
.0877 
.0862 


Lbs. 

1485 
1491 
1491 
1491 
1485 
1491 
1491 
1491 
1491 
1491 


Inch 

0. 2795 
.2795 
.2785 
.2805 
.2790 
.2796 
.2788 
.2798 
.2800 
.2795 


Inch 

0. 2679 
.2675 
.2675 
.2675 
.2675 
.2675 
.2675 
.2675 
.2675 
.2675 


Inch 

0.0867 
.0865 
.0863 
.0880 
.0866 


Lbs. 

1237 
1243 
1243 
1243 
1237 
1243 
1243 
1243 
1243 
1243 


Inch 


2.... 






3 






4.... 






5 






6-.. 

7-... 
8.... 
9.... 
10.... 


0. 0837 
.0842 
.0843 
.0835 
.0835 


0. 0867 
.0872 
.0864 
.0880 
.0868 


Av. 


.0838 








.0851 




.0865 








.0868 




.0870 



















o Load in pounds equivalent to 40 cxx> Ibs./in. 



b Load in pounds equivalent to 38 000 Ibs./in.' 



Experiments on Copper Crusher Cylinders 



II 



Notes on Tabi^e i. — Experiments were made upon copper 
crusher cylinders of Series I. The first and second compressions 
were made January 31, 191 9. The third compression was made 
February 13, 191 9. All three compressions were made under con- 
dition (2), stated above, keeping beam balanced for about 30 
seconds after balance was obtained. The rest of the compressions 



o.oero 
































^ 


r 




6 












/ 


6 


















/ 




















/ 


i. 


















/ 
















% 






/ 




















( 


V 


















































/n /en^f/? of 
copper cy//r?c/Gr^ 
anc/er cr ^er/t^s 
of comp/'ess/ons 
of the. ^c?m& 

/'nfen^/t/es 


'^^.os^o 




























3 


























(0 
















z 


















^ 1 


1 








1 




^^*^ 





? 


^ 




?'3 


'y 








AJ, 



Thousanc/ pounces pGr s<7. /n. 

Fig. 3. — Change of length of copper cylinders upon compression 

(compressions 4-8) were made May 17-19, 191 9, under condition 
(i), with single application of load for about 2>^ seconds. 

As is shown in Fig. 3, the length of the copper cylinders decreases 
considerably under repeated application of the same and even 
smaller loads ; this is in spite of the fact that the first three com- 
pressions were made keeping the beam in a balanced position for 
about 30 seconds. 



12 



Technologic Papers of the Bureau of Standards 



TABLE 2. — ^Experiments on Repeated Application of Decreasing Loads 

Li= length of cylinders after applying pressure of 30 000 lbs./in.2 for about 30 seconds. 
L2= length of cylinders after applying pressure of 28 000 lbs./in.2 for about 2\ seconds. 
L3= length of cylinders after applying pressure of 25 000 lbs./in.2 for about 2\ seconds. 



No. 


L 


D 


A 


Load 
equiv- 
alent 
to 30 000 
lbs./in.2 


L-Li 


maxi- 
mum 


Load 

equiv- 
alent 
to 28 000 
lbs./in.2 


L-U 


Load 
equiv- 
alent 
to 25 000 
lbs./m.2 


Lz 


L-Lz 


1 


Inch 

0. 5010 
.5001 
.4999 
.5010 
.5006 
.5002 
.4998 
.5000 
.5005 
.5003 


Inch 

0. 2517 
.2517 
.2515 
.2517 
.2515 
.2515 
.2518 
.2516 
.2515 
.2514 


Incha 

0. 0497 
.0497 
.0496 
.0497 
.0496 
.0496 
.0497 
.0497 
.0496 
.0495 


Pounds 

1491 
1491 
1488 
1491 
1488 
1488 
1491 
1491 
1488 
1485 


Inch 

0. 0486 
.0496 
.0482 
.0475 
.0481 
.0482 
.0468 
.0468 
.0467 
.0482 


Inch 

0. 2674 
.2675 
.2671 
.2668 
.2670 
.2670 
.2663 
.2668 
.2677 
.2665 


Pounds 

1391 
1391 
1388 
1391 
1388 
1388 
1391 
1391 
1388 
1386 


Inch 

0. 0491 
.0505 
.0494 
.0496 
.0507 
.0505 
.0483 
.0484 
.0484 
.0501 


Pounds 
1243 
1243 
1240 
1243 
1240 
1240 
1243 
1243 
1240 
1237 


Inch 

0. 4515 
.4496 
.4502 
.4500 
.4499 
.4487 
.4505 
.4505 
.4503 
.4493 


Inch 

0. 0495 
.0505 
.0497 
.0510 
.0507 
.0515 
.0493 
0495 


2 


3 


4 


5 


6 


7 


8 


9 


0502 


10 


.0510 




Average 










.0478 






.0495 






.0503 



















:^ 
Q 

Fig. 4. — Change of length of copper cylinders upon compression 

Notes on TabIvE 2. — Experiments were made with copper 
cylinders of same stock as those of Table No. i . The first com- 
pression was made February i, 191 9, with load of 30 000 pounds 
per square inch applied under condition (2), keeping the beam 
balanced for about 30 seconds. 

The second and third compressions were made May 20, 191 9, 
with single application of load 28 000 and 25 000 pounds per square 
inch for about 2>^ seconds under condition (i). Fig. 4 indicates 
that repeated application of decreasing loads gradually decreases 
length of cylinders (within certain limits). 



^\ jT' />^ 
















Oo/o 












, 


3 


,0^0 






^ 


z 


"-"■ 








,^ 


^ 














r/ 














/n /en^f-h 0/ cop- 
per oy//r?'ders c/ncfer 
asGr/GS of com- 
press/ons of decreos- 
/n (^ /n -fens/ fy 


0^70 
















J 



Experiments on Copper Crusher Cylinders 
TABLE 3. — ^Experiments on Repeated Application of Same Load 



13 



No. 


L 


D 


A 


Load 
equiva- 
lent to 
40 000 
Ibs./m.2 


Di 
maxi- 
mum 


mini- 
mum 


L-Li 


L-U 


L-Lz 


1 


Inch 
0. 4010 
.4008 
.4005 
.4004 
.4005 
.4002 
.4002 
.4007 
.4004 
.4001 


Inch 

0. 2265 
.2260 
.2256 
.2261 
.2262 
.2267 
.2267 
.2262 
.2266 
.2261 


Inch 2 
0. 04029 
. 04012 
. 03997 
. 04015 
. 04018 
. 04036 
. 04036 
. 04018 
. 04033 
. 04015 


Pounds 
1612 
1604 
1599 
1606 
1607 
1614 
1614 
1607 
1613 
1606 


Inch 
0. 2500 
.2485 
.2490 
.2468 
.2483 
.2498 
.2502 
.2493 
.2494 
.2486 


Inch 
0. 2350 
.2350 
.2350 
.2350 
.2350 
.2350 
.2350 
.2350 
.2350 
.2350 


Inch 

0. 0618 
.0586 
.0608 
.0547 
.0579 
.0602 
.0603 
.0593 
.0592 
.0587 


Inch 


Inch 


2 


0. 0616 
.0645 


0. 0638 


3 


.0658 


4 . 




5 


.0614 
.0630 
.0633 
.0630 
.0624 
.0618 


.0640 


6 


.0646 


7 


0654 


8 


.0657 


9 


.0644 


10 


0635 






Average 




, 










.0592 


.0626 


0646 










1 







No. 


L-U 


maxi- 
mum 


Di 
mini- 
mum 


L-U 


maxi- 
mum 


D, 
mini- 
mum 


L-U 


L-U 


L-Lg 


1 


Inch 


Inch 

0. 2525 
.2514 
.2514 
.2498 
.2505 
.2519 
.2520 
.2516 
.2519 
.2508 


Inch 
0. 2386 
.2386 
.2386 
.2386 
.2386 
.2386 
.2386 
.2386 
.2386 
.2386 


Inch 

0. 0687 
.0696 

.0670 
.0702 
.0682 
.0700 
.0693 
.0675 


Inch 
0. 2530 
.2517 
.2522 
.2505 
.2510 
.2532 
.2534 
.2526 
.2534 
.2518 


Inch 

0. 2405 
.2405 
.2405 
.2405 
.2405 
.2405 
.2405 
.2405 
.2405 
.2405 


Inch 


Inch 


Inch 


2 


0. 0673 
.0682 


0. 0697 
.0714 


0. 0709 
.0736 


0735 


3 


.0753 


4 


5 


.0659 
.0670 
.0666 
.0685 
.0675 
.0665 


.0682 
.0708 
.0698 
.0709 
.0717 
.0693 


.0694 
.0719 
.0721 
.0727 
.0734 
.0710 


.0703 
0726 


6 


7 


0740 


8 


.0746 
0748 


9 


10 


.0732 






.0672 






.0688 






.0702 


.0718 


.0735 













TABLE 4. — ^Experiments on Repeated Application of Same Load 



No. 


L 


D 


A 


Load 

equiva- 
lent to 
32 000 

lbs./in.2 


Di 
maxi- 
mum 


Di 
mini- 
mum 


L-U 


1 


Inch 

0. 4001 
.3998 
.3999 
.4000 
.4002 
.3998 
.4005 
.4002 
.4000 
.3997 


Inch 

0. 2260 
.2260 
.2264 
.2270 
.2264 
.2264 
.2262 
.2264 
.2264 
.2260 


Inch2 
0. 04012 
. 04012 
.04026 
. 04047 
.04026 
. 04026 
. 04018 
.04026 
. 04026 
.04012 


Pounds 
1284 
1284 
1288 
1295 
1288 
1288 
1286 
1288 
1288 
1284 


Inch 

0. 2408 
.2408 
.2409 
.2425 
.2413 
.2410 
.2410 
.2414 
.2414 
.2415 


Inch 

0. 2295 
.2295 
.2295 
.2295 
.2295 
.2295 
.2295 
.2295 
.2295 
.2295 


Inch 
0. 0410 
.0389 
.0388 
.0409 
.0401 
.0391 
.0400 
.0402 
.0404 
.0403 


2 


3 


4 


5 


6 .... 


7 


8 


9 


10 




Average 












.0400 




1 











14 Technologic Papers of the Bureau of Standards 

TABLE 4. — ^Experiments on Repeated Application of Same Load — Continued 



No. 


L-U 


L-Lz 


L-Li 


L-U 


maxi- 
mum 


r>6 
mini- 
mum 


L~U 


1 


Inch 

0.0425 
.0407 
.0407 
.0430 
.0420 
.0418 
.0417 
.0426 
.0430 
.0423 


Inch 

0. 0450 
.0430 
.0438 
.0444 
.0434 
.0445 
.0432 
.0441 
0456 
.0450 


Inch 

0. 0481 
.0445 
.0458 
.0458 
.0445 
.0455 
.0446 
.0461 
.0468 
.0469 


Inch 

0.0492 
.0454 
.0469 
.0473 
.0460 
.0469 
.0472 
.0482 
.0482 
.0480 


Inch 

0.2442 
.2430 
.2438 
.2447 
.2435 
.2435 
.2438 
.2440 
.2430 
.2442 


Inch 

0. 2345 
.2345 
.2345 
.2345 
.2345 
.2345 
.2345 
.2345 
.2345 
.2345 


Inch 
0. 0510 


2 


.0472 


3 


.0488 


4 


0480 


5 


.0474 


6 . . 


0477 


7 


.0489 


8 


.0494 


9 


.0497 


10 


.0498 






Average 


.0420 


.0442 


.0459 


.0473 






0488 











TABLE 5. — ^Experiments on Repeated Application of Same Load 



No. 


L 


D 


A 


Load 

equivalent 

to 20 000 

lbs./m.2 


maxi- 
mum 


Dx 
mini- 
mum 


L-Li 


1 


Inch 

0. 4000 
.4001 
.4000 
.4000 
.4002 
.4000 
.3999 
.4000 
.4000 
.4002 


Inch 

0. 2256 
.2257 
.2267 
.2257 
.2263 
.2263 
.2262 
.2255 
.2261 
.2263 


Inch 2 
0. 03997 
. 04001 
. 04036 
. 04001 
. 04022 
. 04022 
. 04019 
. 03994 
. 04015 
. 04022 


Pounds 
799 
800 
807 
800 
804 
804 
803 
799 
803 
804 


Inch 

0. 2315 
.2319 
.2332 
.2328 
.2332 
.2323 
.2328 
.2323 
.2319 
.2324 


Inch 

0. 2265 
.2265 
.2270 
.2260 
.2265 
.2270 
.2265 
.2265 
.2265 
. 2265 


Inch 
0165 


2 


.0161 


3 


0172 


4 


.0185 


5 


0177 


6 


.0161 


7 


.0172 


8 


.0175 


.9 


.0156 


10 


0164 






Average . ...... 














0169 



















No. 


L-U 


L-Lz 


L-Li 


L-Lo 


maxi- 
mum 


Z>6 

mini- 
mum 


L-L^ 


1 . . .. 


Inch 

0. 0187 
.0181 
.0182 
.0196 
.0199 
.0173 
.0191 
.0195 
.0164 
.0175 


Inch 

0. 0196 
.0194 
.0194 


Inch 

0. 0202 
.0207 
.0205 


Inch 

0. 0207 
.0208 
.0213 


Inch 

0. 2328 
.2334 
.2343 


Inch 

0. 2264 
.2264 
.2264 


Inch 
0216 


2 


.0220 


3 


0218 


4 




5 


.0213 
.0182 
.0204 
.0207 
.0184 
.0188 


.0221 
.0191 
.0212 
.0219 
.0191 
.0205 


.0233 
.0197 
.0228 
.0223 
.0200 
.0214 


.2352 
.2336 
.2346 
.2338 
2341 
.2340 


.2264 
.2264 
.2264 
.2264 
.2264 
.2264 


-0246 


6 


0209 


7 


0235 


8 


0236 


9 - .. 


0205 


10 


0226 








.0184 


.0196 


.0206 


.0214 






.0223 












Experiments on Copper Crusher Cylinders 



15 



NoTBS ON Tabi.es 3, 4, AND 5. — These tables represent the 
results of experiments with cylinders of Series No. 2 by subject- 
ing them to repeated compressions with single application of 
same load for about 2}4 seconds. 

The repeated loads were: 



Table 


Load 


3 


LbS./iH.2 

40 000 
32 000 
20 000 


4 


5 





0.070 

I 

I 

















-^ 












^^ 












^ 




■ ^< 


■>ooo 


/i}S 


/^' 


-^ 


//? 














































^^ 












^^ 




3>. 


^ooc 


/bs 


per 


^9 ' 


n 


of ccppper crusher c y//nders 
under rcpeofGcf conopnsss/ons 








eo<. 


















'OO , 


^s 


per 


s<^ 


/n. 































s 



//umi:>e^r of Compress/ons 

of length of copper cylinders upon repeated compression 



Fig. 5.- 

All results are shown in Fig. 5. 

The following conclusions may be drawn from these curves: 
(i) The length of cylinders decreases considerably with tlie 
number of times the load is applied. 



i6 



Technologic Papers of the Bureau of Standards 



(2) This change also decreases sHghtly with number of appli- 
cation of load as the hardness of copper increases. 

(3) The slope of the curve representing results of repeated 
compression with the load P is steeper than slope of curve rep- 
resenting results of repeated compression with the load Q if load 
P is greater than Q. 

(6) EXPERIMENTS ON EFFECT OF DURATION OF COMPRESSION APPLIED UNDER 

CONDITION (1) 

TABLE 6. — ^Experiments on Effect of Duration of Compression Applied Under 

Condition (1) 

Li= length of cylinders after appl3dng pressure of 40 000 lbs./in.2 for about Z\ seconds. 



No. 


L 


D 


A 


Load 
equiva- 
lent to 
40 000 
Ibs./in. 2 


L-Li 


No. 


L 


D 


A 


Load 
equiva- 
lent to 
40 000 
Ibs./in. 2 


L-U 




Inch 
0. 3999 
.4001 
.4002 
.4000 
.3997 
.3999 
.3998 
.4001 
.3998 


Inch 
0. 2258 
.2262 
.2266 
.2257 
.2263 
.2260 
.2265 
.2259 
.2260 


Inch 2 
0. 04004 
. 04018 
. 04033 
.04001 
. 04022 
. 04012 


Lbs. 

1601 
1607 
1613 
1600 
1609 
1604 


Inch 
0. 0587 
.0588 
.0587 
.0570 

.0579 
.0591 
.0589 
.0601 


10 


Inch 
0.3999 
.4002 
.4001 
.3999 
.4000 
.3999 


Inch 

0. 2264 
.2260 
.2257 
.2259 
.2264 
.2257 


Inch 2 

0. 04026 
. 04012 
. 04001 
. 04008 
. 04026 
.04001 


Lbs. 

1610 


Inch 

n 058.'? 




11 


1604 0589 




12 


I6O0' . 0579 




13 


1603 0609 




14 


1 
1610 . 0596 




15 


1600 . 0592 


7...^ 


Average. 




. 04029 ioi^ 
. 04008| 1603 
.04012' 1604 










.0588 




























TABLE 7. — ^Experiments on the Effect of Duration of Compression Applied 

Under Condition (1) 

Li= length of cylinders after applying pressure of 40 000 lbs./in.2 for about 25 seconds. 



No. 


L 


D 


A 


Load 

equivalant 

to 40 000 

Ibs./in. 2 


L-Li 


1 


Inch 
0. 3999 
.4002 
.3999 
.4002 
.3999 
.3999 
.3998 
.4001 
.3999 
.4000 
.4002 
.4002 
.4000 
.3998 
.3999 
.3998 


Inch 
0. 2256 
.2264 
.2262 
.2265 
.2262 
.2261 
.2256 
.2263 
.2267 
.2262 
.2257 
.2257 
.2264 
.2262 
.2263 
.2261 


Inch 2 
0. 03997 
.04026 
. 04018 
.04029 
. 04018 
. 04015 
. 03997 
. 04022 
. 04036 
. 04018 
. 04001 
. 04001 
. 04026 
. 04018 
. 04022 
. 04015 


Pounds 

1598 
1610 
1607 
1612 
1607 
1606 
1598 
1609 
1614 
1607 
1600 
1600 
1610 
1607 
1609 
1606 


Inch 

0601 


2 




3 




4 


.0594 


5 


.0609 


6 


.0600 


7 


0604 


8 


. 0603. 


9 


0600 


10 


.0579 


11 


.0580 


12 


.0608 


13 


.0578 


14 




15 


0602 


16 


.0611 
















.0598 















Experiments on Copper Crusher Cylinders 

TABLE 8. — ^Experiments on Effect of Duration of Compression Applied Under 

Condition (1) 
Li^^ length of cylinders after applying pressure of 40 000 lbs./in.2 for about 5 seconds. 



17 



No. 


L 


D 


A 


Load 

equivalent 

to 40 000 

lbs./in.2 


L-U 


1 


Inch 

0. 3999 
.4009 
.4002 
.4001 
.4001 
.3998 
.4002 
.4002 
.3999 
.4000 
.4000 
.4000 
.4002 
.3998 
.3999 


Inch 

0. 2266 
.2263 
.2256 
.2265 
.2260 
.2258 
.2256 
.2265 
.2265 
.2256 
.2257 
.2267 
.2257 
.2260 
.2259 


Inch 2 
0. 04033 
. 04022 
. 03997 
. 04029 
. 04012 
.04004 
. 03997 
.04029 
. 04029 
. 03997 
. 04001 
. 04036 
. 04001 
. 04012 
. 04008 


Pounds 

1613 
1609 
1598 
1612 
1604 
1601 
1598 
1612 
1612 
1598 
1600 
1614 
1600 
1604 
1603 


Inch 
0. 0579 


2 


.0600 


3 


.0597 


4 


.0593 


5 


0585 


6 


; 0583 


7 


.0592 


8 


.0592 


9 


.0595 


10 


0586 


11 


.0593 


12 




13 


.0609 


14 


.0595 


15 


.0609 
















.0593 















Notes on TabIvES 6, 7, and 8. — In this case experiments were 
made upon the cyHnders of Series No. 2. Experiments consisted 
of compressions of 40 000 pounds per square inch appHed under 
condition (i) for different periods, 2}^, 5, and 25 seconds. Average 
changes in length are 0.0588, 0.0593, and 0.0598 inch, respectively. 
These experiments show slight increase of total set with increased 
time of application of load. 

(c) EXPERIMENTS ON EFFECT OF TEMPERATURE OF ANNEALING 

TABLE 9. — Experiments on Effect of Temperature of Annealing 

[These copper cylinders were annealed at 1200° F (650° C).] 



No. 


L 


D 


A 


Load 
equiva- 
lent to 

30 000 
lbs./in.2 


maxi- 
mum 


L-Li 


Load 
equiva- 
lent to 
35 000 
lbs./in.2 


L-L2 


Load 

equiva- 
lent to 
40 000 
lbs./in.2 


L-U 


1 


Inch 

0. 5002 
.5000 
.5000 
.5000 
.5003 
.5000 
.5002 
.5001 
.5001 
.4999 
.5002 
.5000 


Inch 

0. 2223 
. 2225 
.2226 
.2215 
.2221 
.2226 
.2231 
.2228 
.2225 
.2225 
.2218 
.2222 


Inch 2 
0. 03881 
. 03888 
. 03892 
. 03853 
. 03874 
. 03892 
. 03909 
. 03899 
. 03888 
. 03888 
. 03864 
. 03878 


Pounds 
1164 
1166 
1168 
1156 
1162 
1168 
1173 
1170 
1166 
1166 
1159 
1163 


Inch 

0. 2355 
.2356 
.2359 
.2342 
.2351 
.2357 
.2360 
.2361 
.2359 
.2355 
.2345 
,2353 


Inch 

0. 0478 
.0478 
.0482 
.0473 
.0476 
.0487 
.0472 
.0480 
.0489 
.0477 
.0476 
.0486 


Pounds 
1358 
1361 
1362 
1349 
1356 
1362 
1368 
1365 
1361 
1361 
1352 
1357 


Inch 
0. 0628 
.0626 
.0624 
.0614 
.0624 
.0626 
.0610 
.0627 
.0627 
.0621 
.0616 
.0630 


Pounds 

1552 
1555 
1557 
1541 
1550 
1557 
1564 
1560 
1555 
1555 
1546 
1551 


Inch 

0. 0774 


2 


.0780 


3 


.0775 


4 


.0764 


5 .. 


.0772 


6 


.0783 


7 


.0772 


8 . 


.0774 


9 


.0786 


10 


.0772 


11 


.0769 


12 


.0783 






Average - . 












.0480 




.0623 




.0775 





















1 8 Technologic Papers of the Bureau of Standards 

TABLE 10. — ^Experiments on Effect of Temperature of Annealing 

[These cylinders were annealed at 1000° F <540'' C)] 



No. 


L 


D 


A 


Load 
equiva- 
lent to 
30 000 
lbs. /in.2 


L-Li 


maxi- 
mum 


Load 

equiva - 

lent to 

35 000 

lbs. /in.2 


L-U 


Load 
equiva- 
lent to 
40 000 
lbs. /in.2 


L-Lz 


1 


Inch 
0. 5003 
.5005 
.5010 
.5007 
.5007 
.5004 
.5004 
.5003 
.5004 
.5002 
.5005 
.5002 


Inch 
0. 2249 
.2248 
.2255 
.2250 
.2257 
.2252 
.2250 
.2253 
.2253 
.2251 
.2254 
.2254 


Inch 2 
0. 03973 
. 03969 
. 03994 
. 03976 
. 04001 
. 03983 
. 03976 
. 03987 
. 03987 
. 03980 
. 03990 
. 03990 


Pounds 

1192 
1191 
1198 
1193 
1200 
1195 
1193 
1196 
1196 
1194 
1197 
1197 


Inch 

0.0456 
.0465 
.0446 
.0464 
.0466 
.0458 
.0465 
.0450 
.0458 
.0461 
.0460 
.0454 


Inch 
0. 2382 
.2378 
.2378 
.2381 
.2386 
.2382 
.3281 
.2379 
.2379 
.2378 
.2382 
.2379 


Pounds 

1391 
1389 
1398 
1392 
1400 
1394 
1392 
1395 
1395 
1393 
1397 
1397 


Inch 

0. 0597 
.0603 
.0589 
.0603 
.0609 
.0609 
.0606 
.0595 
.0601 
.0599 
.0604 
.0593 


Pounds 

1589 
1588 
1598 
1590 
1600 
1593 
1590 
1595 
1595 
1592 
1596 


Inch 
0. 0749 


2 


0756 


3 


.0737 


4 


0756 


5 


,0765 


6 


0748 


7 


.0763 


8 


.0733 


9 - 


0746 


10 


.0748 


11 


. 0751 


12 


1596 . 0744 
















.0459 






.0601 


! . 0750 





















^ 






















3. 


, 
























/ 






















/ 


/ 


3 


















B, 


VI 


^ 




1 

N 


















/ 


A 




















/ 


/ 






















// 


/ 






















/ 




















V 
























// 


'z 






















/ 


V 




















^ 


/ 
















^ 


/Ji^cra^e. change 
/n /en<^t/i ofcopp&r 
cy/znc^srs /7 and B 

CO m press /ons 


M .OS30 






/ 


y 


/7 








/ 


/ 










/ 


/ 








\J ,0^^O 


/. 


o 










/9-c 

n- 


7nnea/edaftOOO/= 
KOCfF 


^ 


/' 


< 
















1 1 1 1 1 1 1 



Fig. 6. 



"^ •-'-•- 30 3S H-O 

Thou^cind pound 6 per sq /n 

-Effect of annealing upon the change of length of copper cylinders upon com- 
pression 



1 



Experiments on Copper Crusher Cylinders 



19 



Notes on Tabi.es 9 and 10. — ^These tables represent experi- 
ments with copper cylinders of Series No. 3, annealed at 1000 and 
1 200° F (540 and 650° C) . Different compressions (30 000, 35 000, 
and 40000 pounds per square inch) were made keeping the load 
under condition (i) for about 2)4 seconds. Fig. 6 indicates that 
copper cylinders annealed at 1 200° F are softer than those annealed 
at 1000° F. 

(d) EXPERIMENTS ON INFLUENCE OF INITIAL PRECOMPRESSION WHEN LOADS SUC- 
CESSIVELY APPLIED DIFFER CONSIDERABLY FROM EACH OTHER 

TABLE 11. — ^Experiments on Influence of Initial Precompression when Loads Succes- 
sively Applied Differ Considerably from Each Other 

Li== length of cylinders after applying pressure of 20 000 lbs./in.2 for about 23>^ seconds. 
L2= length of cylinders after applying pressure of 32 000 lbs./in.2 for about 2)4 seconds. 
L.3= length of cylinders after applying pressure of 40 000 lbs./in.2 for about 23/2 seconds. 



No. 


L 


D 


A 


Load 
equiva- 
lenc to 
20 000 
lbs./in. 2 


L-Li 


Di 
maxi- 
mum 


Load 
equiva- 
lent to 
32 000 
lbs./in. 2 


L-U 


D2 

maxi- 
mum 


Load 
equiva- 
lent to L-U 
40 000 
lbs./in. 2 


maxi- 
mum 


1 


Inch 

0.4000 
.3998 
.3998 
.4000 
.4000 
.3998 
.3998 
.4000 
.3999 
.4001 
.3998 
.4000 
.4000 
.3999 
.3998 


Inch 

0. 2260 
.2264 
.2257 
.2259 
.2253 
.2261 
.2260 
.2260 
.2263 
.2263 
.2265 
.2265 
.2258 
.2263 
.2268 


Inch2 

0. 04012 
. 04026 
. 04001 
. 04008 
. 03987 
. 04015 
. 04012 
. 04012 
. 04022 
. 04022 
. 04029 
. 04029 
. 04004 
. 04022 
. 04040 


Lbs. 

802 
805 
800 
802 
797 
803 
802 
802 
804 
804 
806 
806 
801 
804 
808 


Inch 

0. 0161 
.0168 
.0175 
.0180 
.0156 
.0154 
.0158 
.0150 
.0160 
.0164 
.0175 
.0167 
.0171 
.0176 
.0158 


Inch 

0. 2322 
.2331 
.2327 
.2323 
.2318 
.2322 
.2317 
.2317 
.2322 
.2327 
.2333 
.2326 
.2322 
.2331 
.2332 


Lbs. 
1284 
1288 
1280 
1283 
1276 
1285 
1284 
1284 
1287 
1287 
1289 
1289 
1281 
1287 
1293 


Inch 
0. 0395 
.0404 
.0410 
.0402 
.0400 
.0398 
.0400 
.0375 
.0399 
.0399 
.0413 
.0396 
.0407 
.0406 
.0396 


Inch 
0. 2410 
.2418 
.2413 
.2403 
.2403 
.2408 
.2402 
.2400 
.2414 
.2412 
.2427 
.2412 
.2413 
.2415 
.2420 


Lbs. Inch 
1605 0.0585 
1610 .0596 
1600 . 0607 
1603 n'^Q'; 


Inch 
2481 


2 


.2494 
2494 


3 


4 


.2487 


5 


1595 
1606 
1605 
1605 
1609 
1609 
1612 
1612 
1602 
1609 
1616 




6 


.0594 
.0601 
.0560 
.0586 
.0589 
.0603 
.0588 
.0607 
.0598 
.0590 


2490 


7 


2486 


8 


2476 


9 


.2488 
2490 


10 


11 


.2498 

.2488 

.2494 

2493 


12 


13 


14 


15 


.2498 














.0165 






.0400 






.0593 
























Notes on TabIvE i i . — Here are represented experiments mth 
copper cylinders of Series No. 2. Successive compressions (20 000, 
32 000, and 40 000 pounds per square inch) were made on same c d- 
inders, keeping the load under condition (i) for about 2>^ second's. 

Comparing the average changes in length of cylinders wih 
those of other tables after the first compression, we can conclute 
that in this case change in length depends only on value of lod 
of the last compression, no matter whether previous compressions 
had been made or not. 

After the first compression of 32 000 pounds per square inci, 
Tables 4 and 1 2 show an average L -Lj of 0.0400 inch. After tvo 
compressions, the first of which was 20 000 pounds per square 
inch and the last 32 000 pounds per square inch, Table No. :i 
shows an average L — L2 of 0.0400 inch. 



20 Technologic Papers of the Bureau of Standards 

After first compressionof 40 000 pounds per square inch 



Table No. 


Results of 
first com- 
pression 
L-Li 




Inch 

0. 0588 
.0592 
.0589 
.0588 




It 


19 





After three compressioB, the first of which was 20 000 pounds 
per square inch, the seconc32 000, and the third 40 000 pounds per 
square inch, Table 11 sbws an average L — L^ of 0.0593 inch. 
Comparing these figures— that is, 0.0400 with 0.0400 inch, and 
0.0593 with 0.0588, 0.059: 0.0589, and 0.0588 inch — we see that 
a very close concordance ^^as obtained. It must be noted, how- 
ever, that this statement may apply only when previous loads 
differ considerably from te last load, as was the case in these 
experiments. (The first loid was 20 000, the second load 32 000, 
and the last load was 40 oco pounds per square inch.) 

(e) EXPERIMENTS ON EFFECT GFl^HTIAL PRECOMPRESSION WHEN DIFFERENCES 
BETWEEN LOADS SUCCISSIVELY APPLIED AHE ONLY SLIGHT 

TABLE 12. — Experiments on the Erect of Initial Precompression when the Differences 
Between the Loads Siccessively Applied are only Slight 

Li= length of cylinders aftei;:essure of 32 000 lbs./in.2 for about 2\ seconds. 
L2= length of cylinders after;:essure of 36 000 lbs./in.2 for about 2J seconds. 
L3= length of cylinders after;.:essure of 38 000 Ibs./in.s for about 2J seconds. 
Z^= length of cylinders after ;.:essure of 40 000 lbs./in.2 for about 2J seconds. 



No. 


L 


D 


A 


Load 

equivalent 

to 32 000 

lbs./in.2 


L-Li 


mayiTniim 


Load 

equivalent 

to 36 000 

lbs./in.2 


1. 
2. 
3. 
4. 
5. 
6. 
7. 
8. 
9. 
10. 
11. 
12. 
13. 
14. 
15. 




Inch 
0. 3998 
.3999 
.3999 
.3999 
.3997 
.3997 
.3999 
.3999 
.3999 
.3999 
.3998 


Inch 

0. 2258 
.2262 
.2257 
.2261 
.2258 
.2267 
.2267 
.2263 
.2265 
.2267 
,2267 
.2260 
.2259 
.2263 
.2268 


Inch' 

0.04004 
.04018 
.04001 
.04015 
.04004 
.04036 
.04036 
.04022 
.04029 
.04036 
.04036 
.04012 
.04008 
.04022 
04040 


Pounds 
1281 
1286 
1280 
1285 
1281 
1292 
1292 
1287 
1289 
1292 
1292 
1284 
1283 
1287 
1293 


Inch 


Inch 


Pounds 


: 


0. 0403 
.0405 
.0384 
.0386 
.0407 
.0409 
.0391 
.0392 
.0409 
.0408 
.0399 
.0398 
.0408 


0. 2410 
.2410 
.2411 
.2407 
.2425 
.2422 
.2415 
.2417 
. 2423 
.2425 
.2413 
.2410 
.2412 


1446 




1440 




1445 




1441 




1453 




1453 




1448 




1450 




1453 




1453 




.3997 


1444 




.3995 
.3996 
.3997 


1443 




1448 


























.0400 






\ 


^^^^^ ! 










P 



















i 



Experiments on Copper Crusher Cylinders 



21 



TABLE 12. — ^Experiments on the Effect of Initial Precompression when the Differences 
Between the Loads Successively Applied are only Slight — Continued 



No. 


L-L2 


Load 

equivalent 

to 38 000 

lbs./in.2 


L-L3 


Load 

equivalent 

to 40 000 

lbs./in.2 


L-U 


Load 
maximum 


1 


Inch 


Pounds 


Inch 


Pounds 


Inch 


Inch 


2 


0. 0496 
.0502 
.0496 
.0495 
.0502 
.0497 
.0499 
.0505 
.0505 
.0509 
.0495 
.0497 
.0504 


1527 
1520 
1526 
1522 
1534 
1534 
1528 
1531 
1534 
1534 
1525 
1523 
1528 


0. 0570 
.0561 
.0553 
.0550 
.0573 
.0557 
.0560 
.0563 
.0568 
.0575 
.0551 
.0553 
.0566 


1607 
1600 
1606 
1602 
1614 
1614 
1609 
1612 
1614 
1614 
1605 
1603 
1609 


0.0624 
.0624 
.0612 
.0607 
.0627 
.0618 
.0616 
.0624 
.0629 
.0638 
.0618 
.0609 
.0620 


0. 2486 


3 


.2495 


4 


.2493 


5 


.2491 


6 


.2496 


7 


.2498 


8 


2494 


9 


.2494 


10 


.2500 


11 


2508 


12 


.2488 


13 


.2489 


14 


.2494 


15 


















Average 


.0500 




.0562 




.0620 













TABLE 13. — ^Experiments on Effect of Liitial Precompression when Differences 
Between Loads Successively Applied are only Slight 

Li= length of cylinders after applying pressure of 36 000 lbs./in.2for about 23^ seconds. 
L2= length of cylinders after applying pressure of 38 000 lbs./in.2for about 2Jxj seconds. 
L3= length of cylinders after applying pressure of 40 000 lbs./in.2for about 2i^ seconds. 



No. 


L 


D 


A 


Load 
equiva- 
lent to 

36 000 
lbs./in.2 


L-U 


maxi- 
mum 


Load 
equiva- 
lent to 
38 000 
lbs./in.2 


L-U 


Load 

equiva- 
lent to 
40 000 
lbs./in.2 


L-Lz 


Dz 
maxi- 
mum 


1 


Inch 

0. 3995 
.3995 
.3994 
.3997 
.3997 
.3998 
.3994 
.3994 
.3998 
.3997 
.4000 
.3996 
.4000 
.3999 
.3998 


Inch 

0. 2260 
.2260 
.2263 
.2268 
.2262 
.2266 
.2257 
.2267 
.2254 
.2255 
.2265 
.2258 
.2257 
.2256 
.2258 


Inch^ 

0. 04012 
. 04012 
. 04022 
. 04040 
. 04018 
. 04033 
. 04001 
. 04036 
. 03990 
. 03994 
. 04029 
. 04004 
. 04001 
. 03997 
. 04004 


Pounds 

1444 
1444 
1448 
1454 
1446 
1452 
1440 
1453 
1436 
1438 
1450 
1441 
1440 
1439 
1441 


Inch 

0. 0488 
.0486 
.0483 
.0500 
.0488 
.0501 
.0483 
.0496 
.2447 
.0500 
.0499 
.0480 
.0505 
.0485 
.0501 


Inch 

0. 2447 
.2445 
.2+18 
.2452 
.2448 
.2451 
.2442 
.2458 
.2448 
.2452 
.2455 
.2445 
.2451 
.2440 
.2450 


Pounds 

1525 
1525 
1528 
1535 
1527 
1533 
1520 
1534 
1516 
1518 
1531 
1522 
1520 
1519 
1522 


Inch 

0. 0545 
.0550 
.0549 
.0559 
.0557 
.0562 
.0553 
. 0561. 
.0555 
.0564 
.0565 
.0550 
.0563 
.0548 
.0563 


Pounds 

1605 
1605 
1609 
1616 
1607 
1613 
1600 
1614 
1596 
1598 
1612 
1602 
1600 
1599 
1602 


Inch 

0. 0610 
.0601 
.0607 
.0622 
.0615 


Inch 

2489 


2 . . 


2488 


3 


2490 


4 


2506 


5 


.2492 


6 




7 


.0609 
.0619 
.0613 


.2489 


8 


. 2501 


9 


2486 


10 




11 


.0625 
.0604 
.0628 
.0606 
.0625 


.2500 


12 ... 


2486 


13 


2492 


14 


.24«3 


15 


2495 






Average 










.0493 






.0556 




.0614 





















/ 



i 



i 



Ttchnvlogic Papers of the Bureau of Standards 



TABLE 14. — Exreriments on the Effect of Initial Precompression when the Differences 
Berween the Loads Successively Applied are only Slight 



L:=le:ir-ji o: cjli-ders arer a: 
L:=le-rJ: of cjliaders aixer '-: 



abo-ut 2-_ seconds. 
abou: 2- - seconds. 



9 

10 

11 

12 

13 

14 

15 



lent to ' L—Li 
38000 
lbs. In.' 



Ih 



lentte 
40000 



L—Ls maxi- 

TTITlTn 




.«>:3 



:5.-.3 


.*?66 


15-5 


.3466 


:;;•:■ 


.3465 


::-J 


.3467 


:5:5 


.3468 


::-o 


.3464 


(B28 


.3467 


0S38 


.3470 


(646 


.3469 


C340 


.3468 


0539 


.3163 



1607 
1598 
1599 
1607 
1600 
1607 
1603 
1610 
1600 
1610 
1599 



Inch 



.0597 
.0616 
.0595 
.0609 
.0621 
.0604 
.0599 
.0596 



.0997 



Inch 
:.2503 

.2487 
.2490 
.2489 
.2494 
.2492 



,2496 
.2486 
.2496 



Avexass. 



TABLE 15. — Effect of laitial Pre: jnpressiin when Differences Between Loads 
Successivelj .A.pplied are only Slight 



32000 



36 000 
lbs. ni.2 



38000 



40000 



5eeTic:e:^:.:-i 

S€e Tables >> 5. I. f. 11, : 



I L—I^=0.(H93 



L-L-:=: ::i2 
Z.— 1.2=0.0556 
L-Z,i= 0.0540 



1.-1.8=0-0620 
I.-I.»=0.0614 
L-L5=0.0606 

L-L:=0.O59O 



XoTES 'jX T.-iJBLES 12. i;. 14, AND i^. — Experiments vrere made 
upon cylinders of the same stock; that is, cylinders of the Series 
No. 2. 

Successive compressions of 32 000. 36 000, 3S 000, and 40 000 
potmds per square inch were made under condition (i), keeping 
tbe load on for about 2>-2 seconds. 

•Average changes in length under initial and successive com- 
pfessions are shown in Table 15. Here are collected from Tables 
3 J 4. 6, II. 12, 13. 14, 16, and 19 average changes of length (total 
sAs . These data show the difference between the change in 
lecrth of cylinders which were compressed at load P and of those 
pre'.iously compressed using a load sHghtiy lower than load P 
and then compressed at load P. 



Experiments on Copper Crusher Cylinders 



23 



It should be noted that in the case where several successive 
loads, differing by 2000 to 4000 pounds per square inch, had 
previously been applied the total change of length increases as 
the number of loads previously appHed increases. All these 
results agree with experiments made with repeated compressions 
of same and smaller (within certain Hmits) loads applied on 
copper which is known to have practically no yield point. 

(/) EXPERIMENTS ON EFFECT OF DURATION OF COMPRESSION APPLIED UNDER 
CONDITION (2) AND COMPARISON OF RESULTS OF DIFFERENT METHODS OF 
LOADING 

TABLE 16, — ^Experiments on Effect of Duration of Compression Applied Under 

Condition (2) 

Li= length of cylinders after applying load of 40 000 lbs./in.2 for about 2}4 seconds. 



No. 


L 


D 


A 


Load 

equivalent 

to 40 000 

Ibs./in.2 


L-U 


Di 
maximum 


1 


Inch 

0.4000 
.4004 
.4000 


Inch 
0. 2261 
.2259 
.2259 


Inch 2 
0. 04015 
. 04008 
. 04008 


Pounds 
1606 
1603 
1603 


Inch 

0.0582 
.0598 
.0587 


Inch 
0. 2485 


2 


.2488 


3 .. . 


2487 


4 




5 


.4003 
.3997 
.4005 
.4000 
.4000 
.4001 


.2259 
.2262 
.2265 
.2260 
.2266 
.2256 


.04008 
.04018 
.04029 
. 04012 
. 04033 
.03997 


1603 
1607 
1612 
1604 
1613 
1599 


.0586 
.0579 
.0588 
.0588 
.0594 
.0601 


.2482 


6 


2484 


7 


2486 


8 


.2488 


9 


2496 


10 


2489 






Average 










.0589 

















TABLE 17. — Experiments on Effect of Duration of Compression Applied Under 

Condition (2) 

Li= length of cylinders after applying pressure of 40 000 lbs./in.2, holding beam balanced for about 5 seconds. 



No. 


L 


D 


A 


Load 

equivalent 

to 40 000 

lbs./in.2 


L-Li 


maximum 


1 


Inch 
0. 3996 
.3996 
.3995 
.3996 
.3995 
.3995 
.3996 
.3996 
.3996 
.3995 
.4002 
.4000 


Inch 
0. 2263 
.2266 
.2263 
.2257 
.2268 
.2265 
.2259 
.2253 
.2263 
.2263 
.2258 
.2255 


Inch 2 
0. 04022 
. 04033 
. 04022 
. 04001 
. 04040 
. 04029 
. 04008 
. 03987 
. 04022 
. 04022 
. 04004 
.03994 


Pounds 

1609 
1613 
1609 
1600 
1616 
1612 
1603 
1595 
1609 
1609 
1602 
1598 


Inch 


Inch 
0. 2494 


2 


.0589 
.0598 
.0611 
.0596 
.0594 


.2497 


3 


.2494 


4 


.2494 


5 


.2505 


6 


2495 


7 


. 2475 


8 


.0596 


.2490 


9 


. 2503 


10 


.0590 
.0604 
.0594 


.2493 


11 


2486 


12 , 


.2487 






Average 










.0597 

















24 Technologic Papers of the Bureau of Standards 

TABLE 18. — ^Experiments on Effect of Duration of Compression Applied Under 

Condition (2) 

Li= length of cylinders after applying pressure of 40 000 Ibs./in.,^ holding beam balanced for about 25 seconds. 





L 


D 


A 


Load 

equivalent 

to 40 000 

lbs./m.2 


L-Li 


Di 
maximum 


1 


Inch 
0. 4007 
.4003 
.4005 
.4003 
.4006 
.4006 
.4005 
.4005 
.4004 
.4008 
.4008 
.4008 


Inch 
0. 2262 
.2261 
.2257 
.2262 
.2266 
.2257 
.2256 
.2258 
.2255 
.2263 
.2265 
.2264 


Inch 2 
0. 04018 
.04015 
. 04001 
. 04018 
.04033 
.04001 
. 03997 
.04004 
. 03994 
.04022 
. 04029 
.04026 


Pounds 
1607 
1606 
1600 
1607 
1613 
1600 
1599 
1602 
1598 
1609 
1612 
1610 


Inch 
0. 0615 
.0591 
.0590 
.0608 
.0609 
.0604 
.0613 
.0615 
.0611 
.0590 
.0611 
.0601 


Inch 
0. 2495 


2 


2489 


3 


.2485 


4 


2494 


5 


. 2505 


6 


.2494 


7 


2488 


8 


.2495 


9 


2486 


10 


.2487 


11 . 


2495 


12 


.2492 
















.0605 

















Notes on Tables i6, 17, and 18. — ^These tables represent the 
results of experiments made with cylinders of same series, No. 2, 
by subjecting them to compressions of 40 000 pounds per square 
inch applied under condition (2) for different periods — 2j4, 5, 
and 25 seconds — that is, holding beam balanced for these different 
periods. 

In order to keep the beam balanced in this case only one addi- 
tional appHcation of same load (impulse) was needed after the 
beam had started to drop. Average changes in length are 0.0589, 
0.0597, and 0.0605 inch, respectively. 

It may be of interest to compare these results with those 
obtained in the experiments where the same load, 40 000 pounds 
per square inch, was held for different periods after the balance 
had been obtained and the beam allowed to drop, and also with 
those results obtained where the same load of 40 000 pounds per 
square inch was appHed successively two times (for 2}4 seconds 
each time), the second load being appHed at some interval after 
the first load was entirely released. 

I . In the case when load of 40 000 pounds per square inch was 
held for different periods after balance was obtained, the beam 
being allowed to drop (Tables 6, 7, and 8), the decrease in length 
of cylinders as compared with the length after compression for 



Experiments on Copper Crusher Cylinders 



25 



2}4 seconds (considering average change for 2)4 seconds is equal 
to 0.0590 inch) is shown here : 



Time of com- 
pression 


Difference in 
decrease 


Seconds 

2K 
5 
25 


Inch 

0.0000 
.0003 
.0008 



2. In case where same load of 40 000 pounds per square inch 
was held for different periods after balance was obtained, but 
holding beam balanced by means of one additional application of 
same load (Tables 16, 17, and 18), these differences were: 



Time of com- 
pression 


Difference in 
decrease 


Seconds 
2M 
5 
25 


Inch 

0.0000 
.0007 
.0015 



3. In the case of one repeated appHcation of the same load of 
40 000 pounds per square inch (Table 4) the difference between 
the decrease in length after first and second applications for 
2}4 seconds each is 0.0626—0.0590 inch = 0.0036 inch. Hence it 
may be seen : (a) That the application of the same load for the 
same period (greater than 3 seconds), but made under condition 
(2) — that is, holding the beam balanced by means of one additional 
application (impulse) of the same load — causes about twice the 
decrease in length observed in the case when the beam is allowed 
to drop after the balance is obtained; (b) that where the load is 
appHed twice (for 2}^ seconds each time), the second load being 
applied at some intervals after the first load has been entirely 
released, the decrease in length is much greater than in the first 
two cases, even when the load is held there as long as 25 seconds. 

{g) EXPERIMENTS ON AGING OF COPPER CYLINDERS OF SERIES No. 2, TABLES 19-25 

The duration of the compression in these experiments was 
about 2X seconds. 



26 Technologic Papers of the Bureau of Standards 

TABLE 19. — Compression Tests Relating to Experiments on Aging of Copper 

Cylinders 
Li= length of cylinders after applying pressure of 40 000 lbs./in.2 



No. 


L 


D 


^ 


Load 

equivalent 

to 40 000 

lbs./in.2 


L-Li 


1 


Inch 

0. 4001 
.4002 
.4001 
.4001 
.4000 
.4001 
.4000 
.4000 
.4002 
.4003 
.4001 
.4002 
.4001 
.4004 
.4003 


Inch 

0. 2266 
.2259 
.2265 
.2258 
.2258 
.2259 
.2253 
.2255 
.2260 
.2265 
.2262 
.2264 
.2257 
.2258 
.2266 


Inch2 

0. 04033 
.04008 
. 04029 
. 04004 
. 04004 
. 04008 
. 03987 
. 03994 
. 04012 
. 04029 
. 04018 
. 04026 
. 04001 
. 04004 
.04033 


Pounds 

1613 
1603 
1612 
1602 
1602 
1603 
1595 
1598 
1605 
1612 
1607 
1610 
1600 
1602 
1613 


Inch 
0. 0599 


2 .. . 


0587 


3 


.0596 


4 . . 


0611 


5 


.0592 


6 . . 


0558 


7 


.0618 


8 


.0555 


9 


0592 


10 


.0606 


11 


.0578 


12 


.0551 


13 . 


0608 


14 


.0598 


15 


.0579 
















.0588 













Notes on TabIvE 19. — The table shows the mean total set of 
cylinders compressed at 40 000 pounds per square inch. The total 
set was 0.0599 inch. 

TABLE 20. — Compression Tests Relating to Experiments on Aging of Copper 

Cylinders 

Li= length of cylinders after applying a pressure of 38 000 lbs./in.2 for about 2J^ seconds. 
L2= length of cylinders after applying a pressure of 40 000 lbs./in.2 for about 2}4 seconds, the pressure of 40 000 
lbs./in.2 being applied 1 hour after the pressure of 38 000 lbs. 



No. 


L 


D 


A 


Load 

equiva- 
lent to 
38 000 

lbs./in.2 


L-Li 


Load 
equiva- 
lent to 
40 000 
Ibs./in.2 


L-U 


1 


Inch 

0.4002 
.4002 
.4004 
.4001 
.4001 
.4005 
.4001 
.4003 


Inch 

0. 2260 
.2261 
.2257 
.2265 
.2260 
.2262 
.2258 
.2263 
.2263 
.2259 
.2261 
.2257 
.2258 
.2258 
.2257 


Inch 2 
0. 04012 
. 04015 
. 04001 
. 04029 
. 04012 
.04018 
.04004 
.04022 
.04022 
.04008 
.04015 
. 04001 
.04004 
.04004 
. 04001 


Pounds 

1525 
1526 
1520 
1531 
1525 
1527 
1522 
1528 
1528 
1523 
1526 
1520 
1522 
1522 
1520 


Inch 

0.0530 
.0552 
.0556 
.0541 
.0554 
.0539 
.0551 
.0529 
.0547 
.0514 
.0517 
.0545 
.0513 
.0544 
.0543 


Pounds 
1605 
1606 
1600 
1612 
1605 
1607 
1602 
1609 
1609 
1603 
1606 
1600 
1602 
1602 
1600 


Inch 

0. 0612 


2 

3 

4 

5 

6 

7 

8. 


.0622 
.0619 
.0616 
.0616 
.0594 
.0608 
,0555 


9 

10 


.4005 
4001 


.0612 


11 


.4002 
.4001 
.4003 
.4003 
.4005 


0588 


12 


.0616 


13 




14 . 


.0606 


15 


.0607 






Averaiye 










0538 




.0608 


Average ^ 













Experiments on Copper Crusher Cylinders 



27 



Notes on Tabi^E 20. — The cylinders were precompressed at 
38 000 pounds per square inch, and one hour later they were com- 
pressed at 40 000 pounds per square inch. Total set was 0.0608 
inch. 

TABLE 21. — Compression Tests Relating to Experiments on Aging of Copper 

Cylinders 

Li= length of cylinders after applying a pressure of 38 000 lbs./in.2 for about 2}4 seconds 
1,2= length of cylinders after applying a pressure of 40 000 lbs./in.2 for about 2>^ seconds, the pressure of 40 000 
lbs. being applied after aging cylinders at 100° C during 28 days. 



No. 


L 


D 


A 


Load 
equiva- 
lent to 
38 000 
lbs./in.2 


L-U 


Load 

equiva- 
lent to 
40 000 

lbs./in.2 


L-U 


1 


Inch 

0.4005 
.4003 
.4006 
.4004 
.4005 
.4001 
.4002 
.4003 
.4003 
.4003 
.4005 
.4000 
.4004 
.4000 
.4002 


Inch 

0. 2257 
.2258 
.2257 
.2257 
.2263 
.2263 
.2264 
.2258 
.2264 
.2265 
.2255 
.2262 
.2270 
.2258 
.2260 


Inch 2 
0. 04001 
. 04004 
.04001 
. 04001 
.04022 
. 04022 
. 04026 
. 04004 
. 04026 
. 04029 
. 03994 
. 04018 
. 04047 
. 04004 
. 04012 


Pounds 

1520 
1522 
1520 
1520 
1528 
1528 
1530 
1522 
1530 
1531 
1518 
1527 
1538 
1522 
1525 


Inch 

0.0551 
.0544 
.0566 
.0519 
.0518 
.0543 
.0563 
.0542 
.0545 
.0539 
.0549 
.0539 
.0549 
.0544 
.0525 


Pounds 
1600 
1502 
1600 
1600 
1609 
1609 
1610 
1602 
1610 
1612 
1598 
1607 
1619 
1602 
1605 


Inch 
0. 0632 


2 ... ... 


.0626 


3 


.0627 


4 


.0596 


5. .. 


0582 


6 


.0618 


7 


.0641 


8 .. ... 


0614 


9 


0627 


10 


.0618 


11. - 


0628 


12 


0619 


13 


0623 


14. . 


0615 


15 


.0615 














.0542 




.0619 

















Notes on Table 21. — This table shows the results for copper 
cylinders, precompressed at 38 000 pounds per square inch, which 
had been held in an electric oven at 100° C for 28 days and 
then compressed at 40 000 pounds per square inch. The final 
total set in this case was 0.0619 inch» 



28 



Technologic Papers of the Bureau of Standards 



TABLE 22. — Compression Tests Relating to Experiments on Aging of Copper 

Cylinders 

Li= length of cylinders after applying pressure of 38 000 lbs./in.2 for about 2^ seconds. 

Z.2= length of cylinders after applying pressure of 40 000 lbs./in.2 for about 2^ seconds, the pressure of 40 000 
lbs./in.2 being applied after aging cylinders at 0° and 100° C alternately during 28 days. 



No. 


L 


D 


A 


Load 
equiva- 
lent to 
38 000 
lbs./in.2 


L-Li 


Load 
equiva- 
lent to 

40 000 
lbs./in.2 


L-U 


1 


Inch 

0.4004 
.4001 
.4001 
.4004 
.4001 
.4002 
.4000 
.4001 
.4003 
.4002 
.4002 
.4000 
.4005 
.4000 
.4005 


Inch 

0. 2260 
.2259 
.2260 
,2263 
.2261 
.2260 
.2259 

. ;^?,fi8 

.2258 
.2267 
.2259 
.2267 
.2254 
.2257 
.2261 


Inch 2 

0. 04012 
. 04008 
.04012 
. 04022 
.04015 
. 04012 
. 04008 
. 04040 
. 04004 
. 04036 
.04008 
. 04036 
.03990 
. 04001 
. 04015 


Pounds 

1525 
1523 
1525 
1528 
1526 
1525 
1523 
1535 
1522 
1534 
1523 
1534 
1516 
1520 
1526 


Inch 

0.0558 
.0556 
.0544 
.0548 
.0543 
.0552 
.0525 
.0539 
.0540 
.0541 
.0530 
.0538 
.0546 
.0538 
.0505 


Pounds 

1605 
1603 
1605 
1609 
1606 
1605 
1603 
1616 
1602 
1614 
1603 
1614 
1596 
1600 
1606 


Inch 
0.0636 


2 . .. 


0630 


3 


.0624 


4 


.0613 


5 


.0624 


6 


.0637 


7 


.0593 


8 


.0626 


9 


.0624 


10 


.0618 


11. 


.0614 
0609 


12 


13 


.0622 


14 


.0615 


15 


0575 






Average ...... .... 










.0540 




.0617 

















Notes on Tabi^e 22. — This table indicates that the final total set 
of 0.0617 inch was obtained on cylinders precompressed at 38 000 
pounds per square inch and aged at o and 100° C, alternately, during 
28 days and then compressed at 40 000 pounds per square inch. 

TABLE 23. — Compression Tests Relating to the Experiments on Aging of Copper 

Cylinders 
1.1= length of cylinders after applying pressure of 38 000 lbs./in.2 for about 2^ seconds. 
L2= length of cylinders after applying pressure of 40 000 lbs./in.2 for about 2^2 seconds, the pressure of 40 000 
lbs./in.2 being applied after aging cylinders at room temperature for 30 days. 



No. 


L 


D 


A 


Load 
equiva- 
lent to 
38 000 
lbs./in.2 


L-U 


Load 
equiva- 
lent to 
40 000 
lbs./m.2 


L-U 


1 


Inch 

0. 4008 
.4008 
.4005 
.4007 
.4007 
.4008 
.4008 
.4005 
.4010 
.4008 
.4011 
.4006 


Inch 

0. 2258 
.2257 
.2257 
.2260 
.2262 
.2259 
.2260 
.2259 
.2260 
.2259 
.2262 
.2267 


Inch 2 
0. 04004 
. 04001 
. 04001 
.04012 
.04018 
. 04008 
. 04012 
. 04008 
.04012 
. 04008 
. 04018 
.04036 


Pounds 

1522 
1520 
1520 
1525 
1527 
1523 
1525 
1523 
1525 
1523 
1527 
1534 


Inch 

0. 0506 
.0561 
.0558 
.0560 
.0550 
.0550 
.0537 
.0527 
.0552 
.0555 
.0553 
.0547 


Pounds 
1602 
1600 
1600 
1605 
1607 
1603 
1605 
1603 
1605 
1603 
1607 
1614 


Inch 

0. 0537 


2 .. 


0636 


3 


.0641 


4 


0617 


5 


.0612 


6 


.0628 


7 


.0613 


8 


.0602 


9.... 


.0616 


10 


.0624 


11 


.0521 


12 


.0618 
















.0546 




.0614 
















Bureau of Standards Technologic Paper No. 185 




.'T^5?5<'P>**59^i3PF'»r,ati'"T>jW-»!sa^r>s;"" i'^>-f -cj 



•.-,«Wv,i¥ .,;» .t-T. 




Fig. 7. — Longitudinal section of copper cylinder annealed at 650° C. X 100 



Bureau of Standards Technologic Paper No. 185 










4 



n : 



~^r.\f- 









Fig. 8. — Cross section of copper cylinder annealed at 6§o° C. X lOO 




Fig. 9. — Longitudinal section of copper cylinder annealed at 650° C. X 100 



Experiments on Copper Crusher Cylinders 29 

TABLE 24. — Compression Tests Relating to the Experiments on Aging of Copper 

Cylinders 

Li= length of cylinders after applying pressure of 38 000 lbs./in.2 for about 2}i seconds. 
L2= length of cylinders after applying pressure of 40 000 lbs./in.2 for about 2}4 seconds, the pressure of 40 000 
lbs./in.2 being applied after aging cylinders at room temperature for 27 days. 



No. 


L 


C 


A 


Load 

equiva- 
lent to 

38 000 
lbs./in.2 


L-Li 


Load 

equiva- 
lent to 
40 000 

lbs./in.2 


L-U 


1 


Inch 

0.4000 
.4001 
.3999 
.3996 
.3996 
.4001 
.4001 
.4001 
.3996 
.4002 
.3999 
.3998 


Inch 

0.2268 
.2260 
.2260 
.2258 
.2265 
.2259 
.2257 
,2256 
.2258 
.2260 
.2255 
.2261 


Inch 2 
0. 04040 
. 04012 
. 04012 
. 04004 
. 04029 
.04008 
. 04001 
. 03997 
. 04004 
.04012 
. 03994 
.04015 


Pounds 

1535 
1525 
1525 
1522 
1531 
1523 
1520 
1519 
1522 
1525 
1518 
1526 


Inch 

0.0547 


Pounds 
1616 


Inch 
0630 


2 




3 . 


.0525 
.0550 
.0529 
.0524 
.0551 
.0544 
.0561 
.0547 
.0541 
.0548 


1605 
1602 
1612 
1603 
1600 
1599 
1602 
1605 
1598 
1606 


0592 


4 


.0621 
0609 


6 


6 


0588 


7 


0526 


8 


0618 


9 


0618 


10 


0621 


11 


0621 


12. . 


0628 
















.0542 




.0616 

















NoTB ON Tabi^BS 23 AND 24. — Cylinders precompressed at 38 000 
pounds per square inch were aged at room temperature for 30 days 
and then compressed at 40 000 pounds per square inch. The 
mean total sets were 0.0614 and 0.0616 inch, respectively. 

Intercomparing all results stated above (Table 25) it may be 
concluded that aging at temperatures of 0-100° C makes the com- 
pressed copper softer. It should be noted, however, that in the 
author's opinion the data in regard to aging is not sufficient; 
such an important problem needs very careful additional experi- 
ments in static as well as impact and firing tests after different 
periods of aging. The above results also are contradictory to 
those of H. W. R. Mason,^^ who found from his impact experiments 
that in copper crushers spontaneous annealing does not take place. 

1^ H. W. R. Mason, Resistance of Copper Crushers during Compression, Arms aud Explosives; July 
1, 1918. 



30 



Technologic Papers of the Bureau of Stafidards 



TABLE 25. — Table Showing Average Results on Effect of Aging on Reduction in 
Length of Compressed Copper Cylinders 



Reference t 
cylinders 



Precompression at 38 OOO lbs-/iiL- 



Compression at +0 000 Ibs./m.2 



Date of precom- 
pression 



Average total 

set of cylinders 

per irLch 



Date of compressiam 



Average 

total set 
of cylin- 
ders per 
inch 



Inch 




Table 24 



0.0540 One hour later of same day, 

June 26, 1919. 
.0535 One hour later of same day, 

Aug. 29, 1919. 
. ::-:; Aug. 27, 1919, after aging at lOO" 

C from July 30 to Aug. 27. 
. 054: Aug. 27, 1919, alter aging at 0" C 

and 100° C alternately from 

July 30 to Aug. 27. 
.0546 Aug. 29, 1919, alter aging at 

room temperature from July 

30 to Aug. 29. 

,0542 ! Aug, 27, 1919, alter aging at 
room temperature from Jtily 

31 to Aug. 27. 



Inch 

0.0606 



.0619 



.0617 



.0614 



.0616 




III. MICROSCOPIC EXAMINATION 

Longitudinal and cross sections of copper cylinders were exam- 
ined microscopically (Figs. 7-15). In all cases the cylinders were 
etched with XH.OH and H,0,.^ 

In order to show distortion of grains under pressure, some 
micrographs were taken of the same spots before and after com- 
pression — that is, the cylinder was etched, the micrograph was 
taken, and the spot marked. Then the cylinder was compressed 
at 30 000 pounds per square inch, and a micrograph of the marked 
spot was taken again. This is shown in Figs. 12-15, where (Figs. 
13 and 15) many slip bands may be seen. 



IV. SUMMARY 

Several conclusions may be drawn from these experiments, 
which onlv confirm the alreadv known phenomena, as well as 
those expected from the known properties of copper : 

I. The length of copper crusher cylinders decreases consider- 
ably under repeated compressions of the same load. The rela- 
tion between this decrease in length and number of times load 
was applied is nearly proportional within certain limits. 



Bureau of Standards Technologic Paper No. 185 




Fig. io. — Longitudinal section of copper cylinder annealed at ^40° C. X 100 




Fig. II. — Cross section of copper cylinder annealed at ^40° C. X 100 



Bureau of Standards Technologic Paper No. 185 




Fig. 12. — Longitudinal section of copper cylinder annealed at 6jO°C. 
JMicrograph represents the spot located midn'ay bases and near to the 
axis of cylinder. X 200 







^^ *^\' 



/'■ >:,^'£^ 




Fig. 13. — Same cylinder and same spot as Fig. 12, hut after compression 
at JO 000 lbs. per square inch. X 200 



Bureau of Standards Technologic Paper No. 185 



-I 


"-y^Jf, 


I 


^ 


t* 




'i. 


r-x''-'->cv-^-,-. 




t:4rr'-^ /' ' • -. 


k 




1 


''-'^"^^^^M^"' 












^- ■ ,r- ** "^--' • 4 ..«. - 


?» 


vr-^-^'"^ %-./.-.-' --> 




' v;i._ ,.^' - ' .'-.- .. 




.. '" * ul,' ^ 








- 



Fig. 14. — Longitudinal section of copper cylinder annealed at 6^0° C. 
Spot is located near one of the bases of the cylinder and very iiear its 
periphery. X 200 







*x 



.^' >^-Xi-'L' 



Fig. 15. — Same cyluulci and same ,v/'u/ as in l'"uj. 14, but after compres- 
sion at JO 000 lbs. per square inch. X ~^o 



Experiments on Copper Crusher Cylinders 31 

2. The change in length with repeated constant loads is greater 
with the greater load. 

3. Repeated application of successive decreasing loads causes a 
gradual decrease in length within certain limits. 

4. The length changes but sHghtly with longer application of 
load when the load is applied in such a manner as to occasion the 
maximum stress only for an instant. 

5. Application of the same load for the same period (greater 
than about 3 seconds), but holding the beam balanced by means 
of one additional application (impulse) of the same load after the 
beam had started to drop, causes about twice the decrease in 
length observed in the previous case, when the beam was allowed 
to drop after balance is obtained. 

6. Double application of the same load for 2}^ seconds each 
time, the second load being applied at some interval after the 
first load has been released, causes a decrease in length much 
greater than in the previous two cases. This holds true even when 
the pressure is applied for as long as 25 seconds in the case of 
paragraphs 4 and 5. 

7. In case the last load is considerably greater than any pre- 
vious loads, the change in length caused by the last load is prac- 
tically independent of the previous loads — that is, it is the same 
as would be obtained by compressing a previously uncom- 
pressed cylinder. 

8. When two successive loads of considerable amount (approxi- 
mately 40 000 pounds per square inch) differing from one another 
by about 2 000 pounds per square inch, are applied, the second 
being greater than the first, the change in length due to the last 
load is considerably greater than that obtained where the pressure 
is applied on previously uncompressed cylinders, and this differ- 
ence increases as the difference between the two loads successively 
applied decreases. 

9. When several successive loads of considerable amount are 
applied, differing by about 2000 pounds per square inch, each 
greater than the preceding load, the total change in length of the 
cylinders due to the last compression increases with the number 
of loads previously applied. 

10. Copper cylinders annealed at 1200° F 650° C are softer 
than those annealed at 1000° F 540° C. 

11. It is probable that aging at temperatures within 0-100° C 
softens the compressed copper somewhat. 



32 Technologic Papers of the Bureau of Standards 

12. Concerning the use of precompressed or uncompressed 
copper cylinders the conclusion from these experiments may be 
drawn for cases when the checking of every copper cylinder by 
precompression is necessary, a precompression of the cylinders at 
a pressiu-e of at least 8000 pounds per square inch below the 
expected maximum pressiu'e can be employed without impairing 
the abiHty of the precompressed cylinders to register the maxi- 
mum pressiure in equally reliable manner as an imcompressed 
cylinder would. 

Washington, October 15, 1920. 



m 



